Open angle glaucoma is a major cause of visual impairment in Black populations. Clinical experience suggests an unusually high glaucoma risk in Barbados, W.I., where most citizens are of African descent. The disease is the major cause of blindness, presenting early and with advanced visual loss. An epidemiologic study is proposed with the major goals of a) measuring the prevalence of glaucoma and its associated impairment, b) evaluating its risk factors, and c) obtaining data to develop interventions to prevent or control visual loss. The proposed research would be the first comprehensive glaucoma study to cover an entire country. Because the disease is a major problem in Black populations, the aims of the proposed study are of widespread public health significance. The secondary goals of the study are to measure prevalence and evaluate risk factors for age-related cataract, macular degeneration, and diabetic retinopathy. Population based epidemiologic data on these diseases are limited or non-existent for Black populations; the proposed study would provide such information at limited additional cost. The above goals would be attained by examining a random sample of 4000 persons 40-84 years in a Ministry of Health polyclinic. Participants could have measurements of intraocular pressure, visual fields, visual acuity, refraction, height, weight, and blood pressure, as fundus photographs and an interview on medical, family, and other risk factor history. Blood testing would be performed on cases and a sample of non-cases. The Fundus Photograph Reading Center of the BES will evaluate the fundus photographs of all participants in the study. The optic discs will be evaluated for glaucomatous changes. Diabetic and age-related changes of the macula will also, be recorded. The fundus photographs will provide an evaluation of fundus pathology on all participants. The final diagnosis will be determined by the Coordinating Center based on positive findings of the clinical examination and the fundus photographs.